What is RBF (replace-by-fee)?
A signalling mechanism that lets an unconfirmed transaction be replaced by a version paying a higher fee.
If a transaction is stuck because fees rose after it was broadcast, RBF lets the sender rebroadcast the same spend with a higher fee. Nodes replace the original in their mempool.
RBF is the reason unconfirmed transactions should not be treated as final. Zero-confirmation acceptance is a business risk decision, not a technical guarantee.
Related terms
Mempool
The set of valid transactions a node has seen but that are not yet in a block — the queue competing for block…
Transactions & feesCPFP (child pays for parent)
Unsticking a low-fee transaction by spending its output in a new, high-fee transaction, making the pair…
Wie es funktioniertConfirmation
A block containing your transaction. Each subsequent block adds another, making reversal exponentially more…
Wie es funktioniertDouble-spend
Spending the same coins twice. Preventing it without a trusted third party is the problem Bitcoin was built…
This definition is part of the Bitcoin Logical glossary. For the fuller explanation, start with Lernen, or see the live numbers on Das Bitcoin-Signal.